Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23D—BURNERS
  • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
  • F23D14/32—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid using a mixture of gaseous fuel and pure oxygen or oxygen-enriched air
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B7/00—Distributors for the molten glass; Means for taking-off charges of molten glass; Producing the gob, e.g. controlling the gob shape, weight or delivery tact
  • C03B7/02—Forehearths, i.e. feeder channels
  • C03B7/06—Means for thermal conditioning or controlling the temperature of the glass
  • C03B7/065—Means for thermal conditioning or controlling the temperature of the glass by combustion with pure oxygen or oxygen-enriched air
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
  • F23M5/00—Casings; Linings; Walls
  • F23M5/02—Casings; Linings; Walls characterised by the shape of the bricks or blocks used
  • F23M5/025—Casings; Linings; Walls characterised by the shape of the bricks or blocks used specially adapted for burner openings
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
  • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
  • F23M2900/00—Special features of, or arrangements for combustion chambers
  • F23M2900/05021—Wall blocks adapted for burner openings
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E20/00—Combustion technologies with mitigation potential
  • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P40/00—Technologies relating to the processing of minerals
  • Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping

Definitions

• the present invention relates to a method for heating by oxycombustion of a material present in a heating zone, such as the distribution channels and in particular the distribution channels for the conditioning of the glass.
• Burners are commonly used as a heating system for heating a material present in a heating zone.
• heating covers not only the supply of energy to a material to raise the temperature, but also the methods of supply of energy to maintain or control the temperature of this material, by example in order to obtain or maintain a more homogeneous temperature across the material.
• a burner is a device used to gather a fuel and an oxidizer for combustion. The fuel and the oxidant are usually conveyed to the heating zone through the burner from outside the enclosure defining the heating zone.
• Air is the traditionally used oxidizer. Combustion with air as an oxidant is called air-fuel combustion.
• the air as oxidant can be advantageously replaced by oxygen-enriched air or by more or less pure oxygen.
• the combustion is then called oxycombustion and the corresponding burners of the oxy-burners.
• This change of oxidizer has the effect of modifying the characteristics of the combustion and even more so those of the flame.
• the burners are chosen according to their power and / or the shape of their flame.
• the burner (s) provide the solid charge with the heating and melting energy necessary for its melting.
• it is therefore generally used high-power burners and whose flames are likely to cover a significant part, or all, of the free surface of the material to be melted in the area of the oven.
• the burner (s) provide the energy necessary for the input of the installation (shaping) downstream, the melt has homogeneous properties such as temperature, viscosity, ... suitable for its treatment in the downstream installation.
• the distribution channels may in particular be equipped with burners which are designed to compensate for the heat losses through the walls of the channels so as to reduce the heterogeneity, especially in terms of temperature of the melt according to the cross section of the distribution channels.
• the burners of the distribution channels are therefore generally low-power burners whose flame is limited to an area near the walls of the channel.
• the power of a burner and the shape of the flame obtained depend essentially on the design or design of the burner and the nature and flow rates of fuel and oxidizer.
• the injector (or nose) of an oxy-burner is generally made of metallic material (steel or refractory steel for example) and is often placed inside a block of refractory material.
• the same burner or the same type of burner at different powers according to the technical characteristics of the process in which the burner or burners are used and / or in such a way as to take account of aging of the chamber. defining the heating zone. In practice, it is found that the high temperatures encountered during the oxycombustion heating process limit the durability (life) of the burner when the burner is not used properly.
• the nose of the burner is generally set back in the quarry block.
• this configuration can also have the effect of a very significant increase in the block temperature and the formation of hot spots in the block and / or the appearance of melting zones of the block that could cause the block to be shut down. and the burner.
• soot formation with carbon deposition on the fuel injector is often accompanied by a change in the position of the flame due to the change in the centering and / or the geometry of the flame; and therefore a change in the efficiency of the heating process.
• volatile materials from the heating zone can be deposited in the block or on the nose of the burner.
• a large deposit of volatile matter in the block / on the nose can also generate a flame deflection which, as previously explained for carbon deposits, reduces the reliability of the burner or even its durability.
• DE-A-102005005735 discloses a method for heating an industrial furnace by means of a tube-in-tube burner.
• the burner has a central fuel injector surrounded by an annular injector of gaseous oxidant, and a cylindrical chamber called mixing and combustion between the injectors and the outlet opening of the burner.
• the combustion that starts in the cylindrical chamber (pre-combustion) is delayed by similar pulse densities of the fuel and oxidant.
• the limited internal volume of the burner chamber, its cylindrical shape and its diameter which is close to the diameter of the burner outer pipe limits the degree of pre-combustion in the chamber and prevents turbulence and recirculation of the gases in the chamber as it is the case with conical burner chambers.
• Figure 1 shows in sectional view a glass distribution channel with the positions of the glass bath and blocks
• FIG. 2 is a diagram of a quarl block used in the glass distribution channels, with the position of the nose of the burner and that of the flame;
• FIG. 3 is a diagrammatic representation of a block in which are indicated the quantities used to calculate the operating index, the index will be explained later in this document.
• FIG. 4 represents the operating matrix of a burner according to the invention as a function of the fuel pulse I F and the oxidant pulse I O ⁇ ,
• FIG. 5 represents an enlarged view of FIG. 4 around zone I; the values of FM and Fm, which will be explained in the remainder of the document, are given for different combinations of the oxidant and fuel pulses;
• FIG. 6 is a diagram of a burner injector tube in tube with the injection of fuel in the center by means of a drill for the creation of a rotational movement, the oxidant being injected on the periphery.
• the present invention relates to a method for heating a material present in a heating zone, and this by the combustion of a fuel with an oxidizer by means of a burner which comprises an injector arranged inside a block. Since the combustion is an oxycombustion, the oxidant has an oxygen content of greater than 21% vol, and more particularly greater than or equal to 50% vol.
• the block defines an inlet passage and a burner chamber.
• the inlet passage has an inlet end and an outlet end.
• the inlet passage opens at its outlet end into the chamber of the block.
• Said chamber of the block comprises a downstream cone and opens through this downstream cone in the heating zone where the material to be heated is located.
• the burner nozzle is mounted in the inlet passage to the outlet end of the inlet passage directly upstream of the chamber.
• the oxidant and fuel conveyed through the injector enter the block through the inlet end of the inlet passage and exit the injector at the outlet end of said passage so as to be injected into the inlet. block room.
• the chamber of the block has a confinement index I conf > 0.10.
• the containment index reflects the degree of containment of the flame within the block. The higher the value of the index, the more the flame will be confined within the chamber of the block.
• the angle ⁇ is 1 ° to 16 °.
• the fuel is injected by the injector into the chamber of the block with a pulse Ip at the outlet of the injector and the oxidant is injected into the chamber of the block by the injector with an Iox pulse at the Release the injector so that 0.7 ⁇ I F ⁇ 3.6 and 0.3 ⁇ Iox ⁇ 5.1, provided that when Iox> 3.8 then I F ⁇ 3.3.
• V s is the speed of said fluid in the outlet section of the injector. It will be noted that, for a mass flow Q m and a given supply pressure, the velocity V s , and thus also the pulse I, of the fluid will depend on the section through which the fluid leaves the injector of the burner.
• the invention thus makes it possible to improve the durability and the reliability of the block and the burner, as well as the energy performance of the burner or, in the case of a retrofit, to replace an existing burner with a more durable and reliable burner.
• the retrofit imposes additional conditions because it involves applying the process in existing installations and the operators of these installations, and in particular the glass installations, are generally more favorable to change the injectors only rather than also to change the refractory blocks or even other elements of the heating zone, given the significant financial cost that that would represent.
• zone III corresponds to: a combination of high fuel pulse and high oxidant pulse, or a combination of high pulse of one of the reactants and a much weaker pulse of the other reagent. Operation of the burner under these conditions presents a high risk of temperature increase of the nose of the burner and a fortiori a risk of soot formation (carbon deposition) on the nose of the burner and degradation of the block aperture.
• zone I is the preferred zone and corresponds to a combination of relatively low fuel momentum and relatively low oxidant impulse.
• the operation of the burner under these conditions has the consequence of obtaining a relatively longer flame but still significantly confined in the chamber of the block, which makes it possible to better transfer the energy to the material to be heated at the outlet of the block, but always close to said block.
• the risk of soot formation on the nose of the burner or degradation of the block is significantly reduced in comparison with the operation of a burner in zone III.
• zone II corresponds to an intermediate operation; the risk of degradation of the nose of the burner and the block is reduced compared to zone III, but higher than in zone I preferred.
• the containment index I con f is usefully less than or equal to 0.35.
• the maximum cone length must not exceed a maximum value which is a function of the oxidant and fuel pulses.
• I conf when I conf ⁇ 0.15 L ' ⁇ (1 / 0.8) x FM (I F, I 0x), when 0.25 ⁇ I conf, L ' ⁇ (1 / 0.8) x Fm (I F , I 0x ), and - when 0.15 ⁇ I conf ⁇ 0.25, L' ⁇ (1 / 0.8) x (FM (IF, IQ) X ) - 10 x fl ⁇ nf
• the oxygen content of the oxidant which is greater than or equal to 50% vol, is preferably greater than or equal to 70% vol and still preferably greater than or equal to 80% vol and more preferably greater than or equal to 87% vol. .
• the burner is a burner tube in tube.
• This type of burner comprises an injector with a central tube for the supply of fuel, this central tube being positioned inside a second tube with creation of an annular passage for the oxidant feed, said annular passage being located around the central tube.
• the fuel then exits the injector through a central section of the outlet opening of the injector and the oxidant exits the injector through an annular section located around the central section in the outlet opening of the injector. .
• the power of the burner is preferably from 0.1 to 500 kW.
• the burner comprises means for imparting a rotation to the oxidant and / or the fuel at the outlet of the injector, the burner preferably being a burner tube in tube comprising a drill inside the tube central for the fuel.
• the method can in particular implement a burner of the type described in US-A-6431467 in the name of American Air Liquide.
• This type of burner more particularly comprises: a first conduit for the passage of the oxidant, a second conduit coaxial with the first conduit and placed inside said first conduit for the passage of fuel, a nozzle placed at the end of the first conduit, - A nozzle placed at the end of the second conduit, a means for swirling the oxidizer placed on the nozzle placed at the end of the second conduit.
• the means for swirling the oxidizer may comprise an elongated object centered aerodynamically at the inside of the nozzle of the second conduit, the inner diameter of said nozzle being greater than the diameter of the elongated object of the means for swirling the oxidant.
• the elongated object may consist of at least one helical rod (drill) over a portion of its length. The injector of such a burner is shown schematically in FIG.
• the burner may also comprise a means for swirling the oxidant placed on the tip placed at the end of the first conduit; this means for swirling the oxidant may consist of a helical spring.
• This type of burner is particularly suitable because it produces a flame of constant length regardless of power variations.
• the method according to the invention is useful for different applications.
• the invention relates in particular to the use of the method as defined above for heating melt in a distribution channel, and in particular for heating molten glass inside a distribution channel for the conditioning of the melt. glass.
• the burner can in particular be mounted in a side wall.
• the fuel is typically a gaseous fuel, such as natural gas, methane, propane and butane.
• the fuel may also be a fluidized jet of a liquid fuel (atomized) or a solid fuel sprayed.
• the longest length L 'of the downstream cone is preferably ⁇ 0.4 m and more preferably L ⁇ 0.3 m.
• the present invention is illustrated below by means of a non-limiting example in the field of glass distribution channels.
• the characteristics of said fluid must be generally controlled. This is the case for example for glass.
• the temperature of the glass coming out of the melting furnace must be controlled before the glass arrives in the forming machines in such a way that the glass acquires the properties suitable for its shaping, such as viscosity for example.
• Distribution channels also called “Feeders” or “ForeHearth” in terms Anglo-Saxons, are used to convey the glass between the output of the melting furnace and the input of the forming machines.
• These distribution channels have heating systems that provide the necessary energy for the glass along its path. Since the glass cools mainly on the ends of the distribution channels, by contact with the refractory materials constituting the distribution channels, it is necessary to transmit the heating energy mainly to the ends of the distribution channels to overcome these losses.
• the heating systems commonly used in the glass distribution channels 10 are burners 11 mounted in the side walls of the channel.
• the injector of said burners 11 is set back inside a block 13 (see Figure 2).
• the temperature of the flame is greater, the radiative transfer is more intense and is exercised in a wavelength range which may be more conducive to the absorptivity of the glass; all of these elements contribute to an improvement in the heat transfer between the flame and the glass compared to a similar system of aerocombustion.
• the proper functioning of the glass distribution channels imposes several criteria with regard to the power and the shape of the flame. Thus, if the flame is too short and remains tight inside the chamber of the block, the glass will be insufficiently heated.
• the present invention enables those skilled in the art to produce burners, and in particular tube-tube burners, which allow the glass distribution channels to function properly and which are durable and reliable, and this in particular as a function of the power required. and the geometry of the block. As already indicated, the invention is particularly useful in case of retrofit.
• the energy transferred to the channel is optimized. Moreover, the temperature level of the block decreases significantly to be below 1500 0 C, as measured experimentally. As the thermal stresses exerted on the block are reduced, the duration of use of the block is lengthened.
• the risk of overheating of the burner nose and burner degradation (blockage of injections) or block is also reduced.
• the temperature measurements have shown that the temperature of the nose of the burner decreased by 100 0 C or more to be generally below 1150 0 C.
• the experimental measurements showed that the risk soot formation is generally increased when the temperature of the nose, composed of steel, exceeds 1150 ° C.
• a remarkable effect of the invention consists in the reduction of a part of the radiative heat flux and on the other hand of the volatile matter received both in the block chamber and from the heating zone.
• a large deposit of volatile materials in the block can cause a deviation of the flame if the latter comes into contact with said deposit and a fortiori a risk of damaging the block.

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• 2007
  • 2007-11-23 FR FR0759283A patent/FR2924201B1/fr active Active
• 2008
  • 2008-11-21 WO PCT/FR2008/052097 patent/WO2009071811A2/fr active Application Filing
  • 2008-11-21 EP EP08857211.0A patent/EP2212620B1/de active Active
  • 2008-11-21 CA CA2704800A patent/CA2704800A1/fr not_active Abandoned
  • 2008-11-21 US US12/743,707 patent/US9074766B2/en not_active Expired - Fee Related
  • 2008-11-21 CN CN2008801169170A patent/CN101868672B/zh active Active
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